Medium2 marksStructured
Using resourcesHighermaterialscomposites

AQA GCSE · Question 06.4 · Using resources

Bicycle frames can also be made from a composite of carbon fibres embedded in a polymer resin.
What description is given in this composite to:
• the carbon fibre component
• the polymer resin component?

How to approach this question

This question is about the structure of composite materials. A composite consists of two main parts with different roles. 1. One part provides the strength and stiffness. What is this part called? 2. The other part surrounds and binds the first part together. What is this part called?

Full Answer

**Carbon fibre:** Reinforcement / fibres **Polymer resin:** Matrix / binder
A composite material is made from two or more constituent materials with significantly different physical or chemical properties which remain separate and distinct at the macroscopic or microscopic level within the finished structure. The two main components are: 1. **The Reinforcement:** This is the material that provides the primary properties like strength and stiffness. It is often in the form of fibres (like carbon fibres, glass fibres) or particles. In this case, the carbon fibres are the reinforcement. 2. **The Matrix (or Binder):** This material surrounds the reinforcement, holding it in place and binding it together. It transfers the load between the reinforcement fibres and protects them from damage. In this case, the polymer resin is the matrix.

Common mistakes

✗ Swapping the terms for the two components. ✗ Using incorrect terminology (e.g., "filler" for the matrix). ✗ Describing the properties (e.g., "strong") instead of the name of the component type ("reinforcement").

Practice the full AQA GCSE Chemistry Higher Tier Paper 2

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